UXPopUpButton

UXPopUpButton shows one selected item from a list. Clicking pops a menu of the items, and choosing one selects it. The item list and the selection (by index, tag, or title) are the pure, testable model. Drawing the closed button and running the menu are the backend’s job. Where the popup is native (macOS NSPopUpButton, Win32 COMBOBOX, iOS UIButton+UIMenu, Android Spinner, GTK GtkDropDown), the OS drops the list and reports the pick back. On GEM the driver runs a menu at the button’s bottom-left.

#use <UXKit>

Overview

UXPopUpButton* align = new UXPopUpButton();
align.addItem((u8*)"Left", 0);
align.addItem((u8*)"Centre", 1);
align.addItem((u8*)"Right", 2);
align.setAction(&controller.onAlign);
content.addSubview(align, UXGeom.make(8, 8, 120, 24));

The first item added becomes the default selection. The action fires after a pick lands, so the handler reads the current value from the sender:

void onAlign(UXControl* sender) {
    i32 tag = ((UXPopUpButton* ?)sender).selectedTag();
    ...
}

Conforms to

• Inherits UXControl: the weak: callback action, enablement, the fire path.

Topics

Items · addItem · removeAllItems · count Selection · selectItem · selectByTag · selectByTitle · selectedIndex · selectedTitle · selectedTag

addItem

void addItem(u8* title, i32 tag)

Appends an item. The tag is yours: a stable id that survives reordering, so handlers use selectedTag instead of the index. The first item added becomes the selection.

removeAllItems

void removeAllItems(void)

Empties the list and clears the selection.

count

i32 count(void)

How many items the list holds.

selectItem

void selectItem(i32 i)

Selects by index (out-of-range picks are ignored). Programmatic selection does not fire the action.

selectByTag

void selectByTag(i32 tag)

Selects the first item carrying the tag.

selectByTitle

void selectByTitle(u8* title)

Selects the first item whose title matches.

selectedIndex

i32 selectedIndex(void)

The current pick, -1 when the list is empty.

selectedTitle

u8* selectedTitle(void)

The current pick’s title, "" when there is none.

selectedTag

i32 selectedTag(void)

The current pick’s tag, -1 when there is none. This is the id a handler usually wants.

Platform appearance

Web

The theme’s popup bezel with its disclosure chevron: the same Aristo art GEM draws, on canvas.

iOS

A real UIButton carrying a UIMenu, the platform’s pull-down idiom. The pick lands through applyNativeSelection.

Android

A real Spinner over an ArrayAdapter. Its selection listener attaches after the initial pick, so only user choices report.

macOS

A real NSPopUpButton.

Windows

A real COMBOBOX (drop-list style).

Linux

A real GtkDropDown over a string list, its selected property feeding the peer.

GEM

The themed bezel; the driver runs the menu at the button’s bottom-left.

Example

A units picker whose tag is the conversion factor id:

UXPopUpButton* units = new UXPopUpButton();
units.addItem((u8*)"Pixels", 0);
units.addItem((u8*)"Millimetres", 1);
units.addItem((u8*)"Inches", 2);
units.selectByTag(savedUnit);
units.setAction(&controller.onUnits);
content.addSubview(units, UXGeom.make(8, 8, 140, 24));